4 The Irish Naturalist. January, 



keen enough to visit the localit}-, which is about eight miles 

 south-west of Tralee. The habitat stated must be quite 

 unlike those in which it lives on the central plain ; there it 

 occurs onl}^ in shallow drains in low, marshy ground, and I 

 have not seen a trace of it in either canal or river. We 

 examined both repeatedly between Monasterevan and Portar- 

 lington on our second visit. Dythiyiia Lcachii, on the contrar3^> 

 did not occur in any of the many drains we examined in a 

 long day's walk across country, nor did we find it in the 

 river, though it was carefully worked at many places. 



Mr. Praeger tells me that the canal is fed at its summit 

 level (279 feet) near Robertstown, Co. Kildare, b}'^ a canal from 

 the south, which conve3\s water from large springs rising in 

 an extensive marsh two miles w^est of Newbridge. Even if 

 B. Leachii were not found in this marsh or near it, the fact 

 would not be a good agument against its being an old 

 member of the native fauna. E- Waller long ago pointed 

 out,^ in his list of the Land and Fresh Water MoUusca of 

 Finnoe, how much the operations of the Drainage Commis- 

 sioners of those da5'S was affecting the habitats of the fresh 

 water species, dr3nng up or shallowing many of the old deep 

 drains. 



P\irther search in the counties named and those near them is 

 very desirable. There should be no real difficulty in distin- 

 guishing the shell, especiallj^ if full-grown ; as Adams'* points 

 out, it bears the same relation in its distinctive characteristics 

 to B. tentaailata that Vivipara coJitcda does to V- vivipara. 

 The w^horls of ^. Leachii are much more convex and suture 

 much deeper ; it has an umbilicus, the mouth and operculum 

 are almost circular; while in B. te7itaculata they are obliquely 

 oval and angulated above. Figure i, D, shows the only likel}" 

 form of the latter that might be mistaken for it, and then only 

 in 3'oung specimens, as full-grown shells are much larger. 



In its foreign distribution B. Lcachii is recorded from places 

 as wide apart as Algiers and Sweden. In England and 

 Ireland it is much more local than B. te7ttaculata, and in the 

 former countrv does not seem to have been found further 



^ Nat. Hist. Review, 1854. p. 84. 



= Manual of the Brit. L. and F. W. Moll, p. 142. 1896. 



